Seems like a really rookie mistake, to assign all your deep cover agents with passport numbers within a specific range..........
This one was under cover in Naples as a jeweler and befriended NATO leadership... and her passport was only one number higher than the two Novichok poisoners in Britain.
To do all the work necessary to set up a deep cover agent and support them for a decade, only to surface them (and several others) because they use a known GRU set of passport numbers... sheeeeeesh.